Method for feeding eggs to an egg breaking apparatus and an egg breaking apparatus

ABSTRACT

The invention relates to an egg breaking apparatus and a method of feeding eggs to an egg breaking apparatus, where eggs are fed to a plurality of egg breaking devices by means of a feed conveyor. Each egg breaking device receives one egg at a time and all egg breaking devices are mounted on a common drive conveyor, where the egg breaking devices are moved in relation to the feed conveyor in a first direction following a substantially vertical first axis at the area of the feed conveyor. The feed conveyor feeds eggs to the egg breaking devices along a substantially horizontal second axis. When near a position at the feed conveyor, the egg breaking devices are tilted about a third axis, which is substantially perpendicular to the first and second axes, in a second direction substantially opposite to said first direction. In a preferred embodiment the egg breaking devices are brought back into their initial, untilted position before or during a period of emptying of the broken egg and after the yolk has left the eggshell upon breaking of the egg, the egg breaking device is preferably tilted downwards in relation to the initial, untilted position, preferably to an angle of approximately 45 degrees below a horizontal plane. During a period of emptying of the egg the egg breaking device may be moved in an uneven pattern, e.g. serrated or corrugated, pattern, causing a vibration of the egg breaking device. It is also preferred, that the egg breaking device performs a second tilting at the end of the period of emptying of the egg. Guiding rail may be provided for guiding the egg breaking devices along a particular track, each egg breaking device preferably being provided with a projecting member capable of interacting with the guiding rail(s).

The present invention relates to a method of feeding eggs to an eggbreaking apparatus, where eggs are fed to a plurality of egg breakingdevices by means of a feed conveyor, each egg breaking device receivingone egg at a time and all egg breaking devices being mounted on a commondrive conveyor, where the egg breaking devices are moved in relation tothe feed conveyor in a first direction following a substantiallyvertical first axis at the area of the feed conveyor, and where the feedconveyor feeds eggs to the egg breaking devices along a substantiallyhorizontal second axis. The invention further relates to an apparatushaving means for exercising such a method of feeding.

When breaking eggs for the purpose of extracting the contents thereof itis important that the eggs are not dropped and that the eggshells arenot broken prematurely or in an inappropriate manner, which may forexample happen if the egg is treated to roughly. In particular thefeeding of eggs from a feeding conveyor to an egg breaking apparatusoperating at high speed is problematic as the eggs may encounter impactloads when being caught at high speed by individual egg breaking devicesof the egg breaking apparatus or may not be caught correctly.

It has been proposed to speed up the eggs to travel with substantiallythe same velocity as the egg breaking devices at the point of delivery,this velocity being approximately twice the velocity used in other partsof egg processing plants. This increase of velocity has been achieved bytransferring the eggs from a first conveyor running at the normalprocessing velocity to a second conveyor running at twice that velocity.This, however, leads to relatively bulky feed conveyor designs with twosuccessive feeding conveyors.

It is therefore the object of the invention to provide a method offeeding eggs to an egg breaking apparatus, where the risk of dropping,unintentional breaking and incorrect catching of the eggs is minimisedwithout necessitating an increase of the proportions of the apparatusused.

This object is met with a method according to the invention, where, whenin a position near the feed conveyor, the egg breaking devices aretilted about a third axis, which is substantially perpendicular to thefirst and second axes, in a second direction substantially opposite tosaid first direction.

The tilting of the egg breaking device causes a brief apparent decreaseof its velocity, which not only decreases the impact loads encounteredby the egg when transferred thereto but also enables a more controlleddelivery as regards accuracy. Once transferred, the egg acceleratestogether with the egg breaking device to the velocity of the commondrive conveyor and there is thus no need for a preceding acceleration ofthe eggs.

In an embodiment, the egg breaking devices are tilted with a velocitycorresponding substantially to the difference between the velocity ofthe feed conveyor and the velocity of the common drive conveyor, meaningthat the effective velocity of the egg breaking device correspondssubstantially to that of the feed conveyor. It is, however, to beunderstood that the velocity of tilting may be less than saiddifference, meaning that the egg breaking devices would travel at aneffective velocity above that of the feeder, but at least some of theadvantages of the reduced difference of velocity would still beachieved.

The velocity of tilting may of cause be different for different portionsof the egg breaking device and in such cases the proportional velocitystated above applies to the portion of the egg breaking device actuallycoming into contact with the egg at receipt thereof. In the most likelyembodiments the part of the egg breaking device intended for holding theegg during breaking thereof is essentially plate shaped and when tiltingsuch a plate shaped part the velocity of the edge furthest from thepoint of rotation will be bigger than the velocity of the rest of theplate, the velocity increasing with the distance from the point ofrotation. As the edge furthest from the point of rotation will normalalso be the one coming into contact with egg first, it is the velocityof this edge, which should fulfil the velocity conditions stated above.

To achieve the optimal use of the apparent decrease of velocity that thetilting of an egg breaking device is performed substantiallysimultaneously with the receipt of an egg from the feed conveyor, butthe exact timing will depend on the design of the feed conveyor, the eggbreaking device, the drive conveyor and the connection between these.

The actual breaking of the eggs may be performed with the egg breakingdevices still in their tilted position, but with the aim of minimizingthe risk of damaging the yolk membrane of the egg it is preferred thatthe egg breaking devices are brought back into their initial, untiltedposition. In particular, the bringing back may take place immediatelyupon receipt of the egg to thereby contribute to the acceleration of theegg.

The untilted position is, however, not optimal with regards to drainingoff all of the albumen and it therefore preferred that after the yolkhas left the eggshell upon breaking of the egg, the egg breaking deviceis tilted downwards in relation to the initial, untilted position,preferably to an angle of approximately 45 degrees below a horizontalplane. The 45-degree angle has proven particularly well suited forachieving an optimal draining of the eggshell, but it is to beunderstood that other angles may also be employed with satisfactoryresult.

To further encourage the emptying of the eggshells it is advantageousthat, during the period of emptying of an egg, the egg breaking deviceis vibrated. This may be achieved by moving the device itself or a baron which it is mounted along an uneven, e.g. serrated or corrugated,surface, causing an alternating upwards and downwards movement of theegg breaking device. A similar effect may, however, also be achieved byinducing an oscillating rotating movement, where the egg breaking deviceis alternatingly turned upwards and downwards corresponding essentiallyto the tilting described above, though possibly with a smaller amplitudeand a different velocity. In this way the contents of the egg are so tospeak shaken out of the eggshell, but it is important to notice that thevibration should not take place until after the yolk has left theeggshell as the yolk membrane could otherwise be damaged.

At the end of the period of emptying of the egg the egg breaking deviceis preferably tilted once more to thereby break any strings of albumenstill connected to the eggshell. By doing this, the amount of albumenremaining in the eggshell at discharge thereof is minimised. Thesecondary tilting is preferably performed at a velocity inflicting ajerk on the albumen, which is thus abruptly torn. In this way the yieldmay be increased by up to 3% in comparison with prior art egg breakingmachines.

Even though the term “tilting” is used to designated both the initialand secondary inclination of the egg breaking device it is to beunderstood that both the velocity of movement, the amplitude and endpositions need not be the same.

In the following examples of embodiments according to the invention willbe described in further detail with reference to the accompanyingdrawing. In the drawing

FIG. 1 depicts an egg breaking apparatus according to the invention,

FIG. 2 shows the track followed by the egg breaking devices,

FIG. 3 shows a perspective representation of a system of guiding railsand abutment parts corresponding to the system shown from the side inFIG. 2,

FIG. 4 shows the egg breaking device seen from the side facing the feedconveyor and in an open position,

FIG. 5 is an illustration corresponding to the one in FIG. 4 but withthe egg breaking device in a closed position, and

FIG. 6-11 shows the egg breaking device seen in a direction parallel tothe third axis in different positions on the track.

An egg breaking apparatus according to the invention may be embodied asshown in FIG. 1. The apparatus shown comprises two separate chains 1, 2mounted on toothed turning wheels 11,12,21,22, where the uppermost chain1 carries a plurality of egg breaking devices 13 and the lowermost chain2 carries a plurality of egg receiving devices 23, the chains serving asdrive conveyors common to all of the egg breaking and receiving devices,respectively. FIG. 1 shows only a few egg breaking and receiving deviceson the respective chains but it is to be understood that in practise thenumber of devices on each chain are larger such that they are evenlyspaced with substantially the same mutual distance on both chains.Similarly, even though FIG. 1 shows only a single row of egg breakingand receiving devices it is to be understood that each of these devicesmay represent a column of devices extending perpendicularly to the planeof the drawing. Such columns are preferably mounted on horizontal barsstretching between two parallel chains, each column including forexample eight or sixteen separate egg breaking or receiving devices.When using four chains instead of the two shown in FIG. 1, the number ofturning wheels is of course also doubled.

A feed conveyor 3 carries eggs 4 towards the uppermost chain anddelivers them to the egg breaking devices 13 at point A, where the eggbreaking devices are moved essentially along a first vertical axis a1and where the delivery of the eggs takes place substantially along asecond horizontal axis a2.

The uppermost chain 1 is driven in a counter-clockwise direction and thelowermost chain 2 in a clockwise direction as indicated by the arrows,the velocity of the two chains being substantially identical. In thisway each egg breaking device 13 will meet an egg receiving device 23 atpoint B and the pair will travel together until reaching the upper rightturning wheel 12 as seen in the FIG. 1.

The actual breaking of the egg 4 takes place in the vicinity of point Band the contents of the egg are then drained from the eggshell into theegg receiving device 23 underneath the egg breaking device 13. As may beseen, the distance between the two chains 1,2 increases with themovement towards the second turning wheel 12 of the uppermost chain 1causing a gradually increasing pull on the albumen and in particular onthe chazala.

As may further be seen from FIG. 1 as well as from FIG. 2 the ascendingportion of the track, where the distance between the two chains 1,2increases as explained above, is equipped with a serrated or corrugatedsurface 14, along which horizontal mounting bars, on which the eggbreaking devices 13 are mounted as described above, travels. This causesa vibration of the egg breaking devices and thus the opened eggshells,which vibration will encourage any remaining albumen to leave theeggshells. The mounting bars may be moved directly along the serrated orcorrugated surface causing an alternating upwards and downwards movementthereof, or they might be provided with guiding arms as explained belowrunning along the serrated or corrugated surface to thereby cause arotation based vibration.

When reaching the upper right turning wheel 12 as seen in FIG. 1 the eggbreaking device 13 travels upwards away from the egg receiving device23, and the emptied eggshells 8 are discharged into the waste receptacle15, from where they may be removed by means of for example a screwconveyor (not shown).

After passing the upper right turning wheel 12, the egg receivingdevices 23 travels onwards along the chain 2 towards the turning wheel22, the distance d between the turning wheels 12 and 22 of the two chainsystems serving as an inspection section, where the contents of the eggreceiving devices may be monitored manually or automatically.

When reaching the underside of the chain 2, the contents of the eggreceiving devices are emptied into one or more product receptaclesdepending on the result of the inspection. In the embodiment shown theapparatus is equipped with four product receptacles; one 24 forreceiving pure albumens, one 25 for receiving pure yolks, one 26 forreceiving mixtures of albumen and yolk and one 27 for receivingotherwise contaminated or unacceptable eggs. For enabling the separatedischarge of albumen and yolk each egg receiving device 23 is equippedwith a yolk holder 231 and an albumen cup 232, which may be emptiedindependently.

As may be seen from FIG. 1, the uppermost chain 1 is considerablyshorter than the lowermost chain 2, meaning that the number of eggbreaking devices 13 is smaller than the number of egg receiving devices23 and that for each process cycle different egg breaking and eggreceiving devices will be paired when meeting at point B. Preferably thenumber of egg receiving devices is twice the number of egg breakingdevices, meaning that only two specific egg receiving devices willreceive the contents of eggs broken by any one of the egg breakingdevice. If, however, it is desired that only the same two devices shouldbe paired during each process cycle the chain systems can be modifiedaccordingly, for example by making the uppermost chain longer, possiblyadding an extra turning wheel (not shown), or by adding a buffer (notshown) delaying the advancement of the egg breaking devices.

FIG. 2 shows the track followed by the egg breaking devices 13 in closerdetails. As may be seen the track deviates from that, which is native toa chain 1 guided about two spaced apart turning wheels 11,12 as shown inFIG. 1. This deviation is achieved by providing each of the egg breakingdevices with projecting guiding arms 133,134 as may be seen in FIGS. 6and 7 carrying guiding wheels 135,136, which runs on a system of rails14,16,17 arranged at an appropriate distance from the native track ofthe chain and/or which comes into abutment against fixed parts (notshown) of the apparatus arranged on or in the vicinity of the rails.

In the embodiment shown the track is delimited by means of guiding rails16,17 arranged two by two, but other embodiments where for example thebreaking devices rest on solitary guiding rail under the influence ofgravity may also be envisaged.

When passing the feed conveyor 3 the egg breaking device 13 is tiltedupwards as indicated with the arrow T1 in FIG. 6 from the initialposition to a tilted position shown in FIG. 7. The tilting of the eggbreaking device is achieved by the arm 133 following the guiding rail 16into the depression 161 as seen in FIG. 7. In the embodiment shown, theegg breaking device is tilted approximately 10 degrees upwards, but thisangle may vary depending on different system requirements.

In the preferred embodiment, the tilting is performed as a rotation ofthe entire egg breaking device, but a separate part of the egg breakingdevice intended for receiving the egg may also be rotatableindependently of the rest. Such an independent part should, however,preferably be connected to the rest of the egg breaking device in amanner allowing mounting, replacement etc. as one unit.

The egg breaking apparatus may of course be provided with additionalmeans (not shown) for transferring the eggs from the feed conveyor 3 tothe egg breaking device 13, such means for example comprising pins,wings, shovels or the like designed to push or lift the eggs off thefeed conveyor and onto the egg breaking devices. Such means may beprovided in connection with the feed conveyor 3, the common driveconveyor 1 or the egg breaking device 13.

The curves shown on the uppermost, substantially horizontal section ofthe guiding rails 16,17 are made for the purpose of repositioning theegg breaking devices before starting a new process cycle.

FIGS. 4 and 5 show the egg breaking device 13 seen from the side facingthe feed conveyor 3. As may be seen the egg breaking device, whichcomprises a lower holding part 30 and an upper retaining part 40, ismounted on a horizontal bar 50 as mentioned above. The retaining part ismoveable in a substantially vertical direction in relation to theholding part to enable it to be moved from the open position shown inFIG. 4 to the closed position shown in FIG. 5. In the embodiment shown,the retaining part is mounted on an arm 41, which may be rotated about apoint of suspension 42 by means of another arm 43 coming into abutmentagainst a fixed part 47 of the frame of the apparatus, which may be seenin FIGS. 2 and 3, the latter arm preferably being provided with anabutment wheel 44. It is, however, to be understood that the retainingpart may for example also be mounted on a substantially vertical arm(not shown), which is moved along its length axis by means of hydraulicor spring actuated means.

In the embodiment shown, the holding part 30 is split in two 30 a, 30 bto give room for a knife part 31 between them, said knife part beenmoveable together with the holding part and the rest of the egg breakingdevice during tilting thereof and further being moveable independentlyof the holding part to enable breaking of the egg shell as will beexplained below.

When passing the feed conveyor 3 for receiving an egg, the holding part30 is in a closed position as shown in FIG. 5 and the retaining device40 is in its upper position as shown in FIG. 4. In the initial positionthe holding part 30 is substantially horizontal, possibly with a slightpositive inclination as shown in FIG. 6 and it is then tilted upwards tothe position shown in FIG. 7 as shown with the arrow T1, the tiltingcorresponding to approximately 10 degrees. The tilting is achieved bymeans of the guiding arm 133 following the track of the guiding rail 16into the depression 161 as explained above, but may also be achieve bymeans of a hydraulic cylinder (not shown) or the like capable ofeffecting both a pull and a pressure on the egg breaking device.Alternatively, the device may be subject to a continuous pull exercisedby means of for example a simple coil spring (not shown), which pull maybe overcome by means of the pressure of a hydraulic means or vice versa.

To keep the egg 4 in place during the subsequent breaking thereof theretaining part 40 is brought down to the position shown in FIGS. 5 and8, whereby it comes into abutment against the upper side of theeggshell. The actual breaking is achieved by lowering a knife portion 31to the position shown in FIG. 8 and then taking it rapidly back to theposition shown in FIG. 9 to thereby penetrate the eggshell. The movementof the knife is initiated by means of an arm 36 carrying an abutmentwheel 37 as shown in FIG. 9 coming into abutment against fixed parts 38of the apparatus, which may be seen in FIGS. 2 and 3.

In principal, the apparatus may function without a retaining part 40,but the presence thereof is much preferred, as it contributesconsiderably to minimising the risk of the egg being incorrectly brokenor dropped.

The retaining part 40 is provided with a projection 45 on its sidefacing the egg. The purpose of this projection is to direct the crack inthe eggshell caused by the knife portion 31, but the egg breaking devicemay function without the projection.

Once the crack in the egg shell has been created, the two halves of theholding part 30 is moved away from each other to the position shown inFIG. 4 by forcing a pair of levers 33,34 towards each other. The knifepart 31 is split in two 31 a, 31 b in the same way as the holding part30 as may be seen from FIGS. 4 and 5 and these two knife members 31 a,31 b are moved to the side together with the two members 30 a, 30 b ofthe holding part, the knife members functioning as detaining edgespreventing the two halves of the eggshell from sliding off the nowinclined portions of the holding part. The movement away from each otherof the two holding and knife members is preferably achieved by bringingthe levers into contact with fixed parts 48 of the apparatus, which maybe seen in FIGS. 2 and 3. During opening the two wing-like side portions46 of the retaining part 40 acts as retaining and guiding means for theeggshell. At the beginning of a new process cycle, the levers are movedback, away from each other by coming into contact with a fixed part 18of the apparatus, which may too be seen in FIGS. 2 and 3.

In the embodiment shown, the two halves are of the holding part 30interconnected by a spring 32 forcing them towards each other, but whichis not in itself strong enough to move them. In the position shown inFIG. 4 the spring it located above the point of connection 35 of the tohalves and thus helps keeping the levers 33,34 together and the holdingpart 30 in its open position. When the two levers are brought into theposition shown in FIG. 5 the spring 32 passed the point of connection 35and will consequently pull the two halves of the holding part 30 towardstheir closed position. The spring may thus be said to always contributeto keeping the two halves of the holding part in their current position.

The angle of opening a between the two knife portions 31 a, 31 b andthus between the two halves of the eggshell is preferably approximately45 degrees, but a wide range of opening angles will serve the purpose aslong as the yolk of the egg may pass through the opening and the eggbreaking device is able to hold securely on to the eggshell.

The holding and retaining parts 30, 40 are kept in these positions untilthe entire contents of the egg have been drained as explained above.

The small differences in the positioning of the holding part 30 of theegg breaking devices shown in FIGS. 6, 8 and 9 are only to be seen asone of number of different embodiments. The important thing is that theknife part should be arranged substantially horizontally during thebreaking, opening and initial emptying of egg to thereby minimise therisk of the knifes cutting trough the yolk membrane either in connectionwith the breaking of the shell or when the yolk leaves the eggshell.Keeping the egg breaking device in a substantially horizontal positionin stead of a tilted position may be said to correspond to holding ashaving razor in an oblique angle in stead of perpendicular to the skin,which will prevent unintentional cutting.

To enable the best possible draining of the albumen remaining in theeggshell once the yolk has been left it, the egg breaking device 13 ispreferably moved to the position shown in FIG. 10, where it is locatedin a downwards angle of approximately 45 degrees in relation to itsinitial position. This movement of the egg breaking device may beperformed suddenly or gradually during the emptying of the egg and theangle of the end position may be varied according to differentparameters such as the viscosity of the albumen of the eggs beingprocessed.

As described above a vibration of the egg breaking device 13 and thusthe opened eggshell may be employed to encourage a larger part of thealbumen to leave the eggshell and an alternating upwards and downwardsmovement of the egg breaking device by turning may serve this purpose.Such a turning should preferably have a substantially smaller amplitudethan the tilting described above, but it is equally preferred that theturning should be performed with the same means as those used for theinitial as well as the finishing tilting.

When reaching the end of the ascending section of the track, i.e. pointC in FIGS. 1 and 2, the egg breaking device is tilted once more asindicated by the arrow T2 in FIG. 10 essentially as described above inconnection with the receipt of the egg. This tilting has the purpose oftearing any strings of albumen still attached to the eggshell and it isto be understood that the velocity of movement of the egg breakingdevice as well as the amplitude and end positions need not be the sameas by the initial tilting. On the contrary, it may be preferred thatthis second tilting happens at a greater velocity than the firsttilting, as the purpose is here a breaking or tearing of the albumen,whereas the first tilting is among others intended to prevent breakingof the eggshell.

To release the emptied eggshell, the retaining part is brought back intothe position shown in FIG. 4 by contact with the fixed part 49 of theapparatus, which may be seen in FIGS. 2 and 3, and the egg breakingdevice is turned to the position shown in FIG. 11. The eggshell thenfalls from the egg breaking device under the influence of gravity, andno additional means are needed for discharging the eggshell.

It is to be understood, that the preferred embodiments of the inventiondescribed in the above are not to be seen as limiting the scope of theinvention. Rather, a person skilled in the art will be able to conceivea number of modifications and combinations of the features describedabove, which will fall under the scope of invention as define by theclaims.

1. A method of feeding eggs to an egg breaking apparatus, where eggs arefed to a plurality of egg breaking devices by means of a feed conveyor,each egg breaking device receiving one egg at a time and all eggbreaking devices being mounted on a common drive conveyor, where the eggbreaking devices are moved in relation to the feed conveyor in a firstdirection following a substantially vertical first axis at the area ofthe feed conveyor, and where the feed conveyor feeds eggs to the eggbreaking devices along a substantially horizontal second axis,characterized in that, when near a position at the feed conveyor, theegg breaking devices are tilted about a third axis, which issubstantially perpendicular to the first and second axes, in a seconddirection substantially opposite to said first direction.
 2. A methodaccording to claim 1, characterized in that the egg breaking devices aretilted with a velocity corresponding substantially to the differencebetween the velocity of the feed conveyor and the velocity of the commondrive conveyor.
 3. A method according to claim 1, characterized in thatthe tilting of an egg breaking device is performed substantiallysimultaneously with the receipt of an egg from the feed conveyor.
 4. Amethod according to claim 1, characterized in that the egg breakingdevices are brought back into their initial, untilted position before orduring a period of emptying of the broken egg.
 5. A method according toclaim 1, characterized in that after the yolk has left the eggshell uponbreaking of the egg, the egg breaking device is tilted downwards inrelation to the initial, untilted position, preferably to an angle ofapproximately 45 degrees below a horizontal plane.
 6. A method accordingto claim 1, characterized in that during a period of emptying of the eggthe egg breaking device is moved in an uneven pattern, e.g. serrated orcorrugated, pattern, causing a vibration of the egg breaking device. 7.A method according to claim 1, characterized in that the egg breakingdevice performs a second tilting at the end of the period of emptying ofthe egg.
 8. A method according to claim 7, characterized in that thesecond tilting of the egg breaking device is performed at a velocityinflicting a jerk on any possible part of the albumen still connected tothe eggshell.
 9. An egg breaking apparatus, comprising a plurality ofegg breaking devices, each capable of receiving one egg at a time andall being mounted on a common drive conveyor, a feed conveyor forfeeding eggs to the egg breaking devices, a plurality of egg receivingdevice, each capable of receiving the contents of only one egg in eachprocess cycle, where the egg breaking devices are movable in relation tothe feed conveyor in a first direction along a substantially verticalfirst axis, and where the feed conveyor conveys the eggs to the eggbreaking devices along a substantially horizontal second axis,characterized in that, when near a position opposite the feed conveyor,the egg breaking device is tilted about a third axis, which issubstantially perpendicular to the first and second axes, in a seconddirection substantially opposite to said first direction.
 10. Anapparatus according to claim 9, characterized in that each egg breakingdevice is pivotably mounted and provided with a projection, such as anarm, which engages a guide track fixed in the apparatus frame duringmovement the egg breaking device along the common drive conveyor.
 11. Anapparatus according to claim 9, characterized in that each egg breakingdevice is slidably mounted and that hydraulic means capable of causing asliding displacement along the first axis of the egg breaking device areprovided.
 12. An apparatus according to claim 9, characterized in thatthe tilting of the egg breaking apparatus is reversible.
 13. Anapparatus according to claim 9, characterized in that it comprises atleast one guiding rail for guiding the egg breaking devices along aparticular track, each egg breaking device preferably being providedwith a projecting member capable of interacting with the guidingrail(s).
 14. An apparatus according to claim 13, characterized in thatthe common drive conveyor comprises chains to which the egg breakingdevices are mounted, directly or indirectly, and that the chains areprovided with projecting members capable of interacting with the guidingrail(s).
 15. An apparatus according to claim 9, characterized in that itcomprises an uneven, e.g. serrated or corrugated, surface over which theegg breaking devices are moved for causing a vibration of the eggbreaking devices.